It is a common occurrence for persons when bushwalking, backpacking or undertaking like activities to become lost. Normally the location of such persons is difficult to detect even with the use of aircraft such as helicopters or the like. Similarly, if a person becomes lost overboard from a ship or other vessel, or if a vessel founders causing say the crew thereof to board liferafts, the location of such persons is extremely difficult. Often, failure to locate persons in the above predicament results in fatalities. Although various means are available to facilitate detection of such persons such as brightly coloured clothing or life jackets which may be worn by the person or dan buoys which may be thrown overboard to indicate the general area where the person has disappeared from a vessel, such means are of limited usefulness because they cannot be visually or otherwise easily located when one is some distance therefrom. Emergency signal beacons for transmitting a radio signal in the result of emergencies are also available, however, such devices are not suited to all situations and often lack reliability.